Hot oil recirculating cooking system

ABSTRACT

Hot oil recirculating cooking system for deep fat frying of food, such as chicken parts, including a cooking pot chamber having a bottom outlet and a top inlet. Through flow conduit means connect the bottom outlet to the top inlet where the returned oil is delivered into the pot chamber by spray nozzles. This conduit means includes a pump and a horizontally oriented, closed, openable cylindrical filter tank containing removable filtering equipment. The cooking pot is transversely rectangular with a pair of its opposed, widely spaced sidewalls shaped inwardly toward each other at the bottom of a frying zone of its chamber to provide a pair of upwardly facing, crowned shoulder ledges. Depending from these shoulder ledges these opposed shaped sidewalls define therebetween a downwardly converging, relatively narrow cold zone deep well closed off by a horizontal bottom section, with the other opposed pair of pot sidewalls being arranged in transversley spaced, vertical planes to define convergingly shaped, narrow end walls of this well. The mergence portions of these shaped sidewalls which define these shoulder ledges and the deep well sidewalls are smoothly convexed inwardly and the well bottom section is smoothly convexed outwardly in bubous fashion. The pot chamber outlet opening is provided oi in one well end wall at the bottom of this bulbous section for effective clean-out of particulate solids into the conduit line. The outlet opening is connected throuh a shut-off valve to an inlet end section of the horizontally oriented filter tank with this inlet section being closed off by a removable lid which carries a valved rain and suction tube. The cylindrical filter chamber has nested therein downstream of its inlet section a removable, rigid, foraminous, cup-shaped basket which supports therein an open-mouth filter bag, and the transverse downstream end of the filter tank has an outlet opening flow connected by a conduit section to the inlet of the pump. The pump outlet is flow connected by a supply conduit section which extends over the rim of the open top of the cooking post down to its chamber for flow connection therein of a nozzle assembly. The nozzle assembly is located at the end wall of the well opposite that which has the outlet opening, and it includes a pair of lateral nozzles each located at one of the mergence shoulder ledges with jet openings thereof directed laterally toward the opposite outlet openingequipped end wall for washing particulate solids off of this shoulder ledge down into the well. Another nozzle of this assembly depends down into the well to direct a jet therefrom along the bulbous bottom section of the latter for sweeping into the outlet opening particulate solids which tend to collect in this section. A lateral, foraminous, food-supporting rack is supported on the pair of shoulder ledges immediately above the pair of lateral nozzles so that pieces of food thereon will be in the hot frying zone of the hot oil pooled in the pot chamber. A small aspirating and bleed aperture is provided in this supply conduit section in the vicinity of the intended surface of the pooled hot oil. Burners are provided externally of the pot chamber on opposite sides of the cold zone deep well for heating the well walls in Their shoulder mergence portions and therebelow, and the oil pooled thereabove in the frying zone.

Waited States Patent [1 1 Pelster et al.

[54] HOT OIL RECIRCULATING COOKING SYSTEM [75] Inventors: Arthur F.Pelster; Eugene C. Johns; Norman C. Sullivan, all of Nashville, Tenn.

[73] Assignee: Kentucky Fried Chicken Corporation, Louisville, Ky. [22]Filed: Feb. 23, 1972 [21] Appl. No.: 228,598

[52] US. Cl ..99/408, 99/403 [51] Int. Cl. ..A47j 37/12 [58] Field ofSearch ..99/403, 408, 355, 99/352, 330, 404; 210/167, 171, DIG. 8

[56] References Cited UNITED STATES PATENTS 2,886,439 5/1959 Eytiuge..99/404 X 2,978,975 4/1961 Rossi ..99/33O 3,483,982 12/1969 Nelson99/408 2,827,379 3/1958 Phelan ..99/330 3,280,722 10/1966 Rahauser....99/330 X 3,036,513 5/1962 Reeves ..99/404 3,495,525 2/1970 Piotrowski..99/403 X Primary ExaminerLeon G. Machlin Att0rney-Elmer R. Helferich,Norman N. Schuttlev, John T. Kelton et al.

[57] ABSTRACT widely spaced sidewalls shaped inwardly toward each otherat the bottom of a frying zone of its chamber to provide a pair ofupwardly facing, crowned shoulder ledges. Depending from these shoulderledges these opposed shaped sidewalls define therebetween a downwardlyconverging, relatively narrow cold zone deep well closed off by ahorizontal bottom section,

[451 May 29, 11973 with the other opposed pair of pot sidewalls beingarranged in transversley spaced, vertical planes to define converginglyshaped, narrow end walls of this well. The mergence portions of theseshaped sidewalls which define these shoulder ledges and the deep wellsidewalls are smoothly convexed inwardly and the well bottom section issmoothly convexed outwardly in bubous fashion. The pot chamber outletopening is provided oi in one well end wall at the bottom of thisbulbous section for effective clean-out of particulate solids into theconduit line. The outlet opening is connected throuh a shut-off valve toan inlet end section of the horizontally oriented filter tank with thisinlet section being closed off by a removable lid which carries a valvedrain and suction tube. The cylindrical filter chamber has nested thereindownstream of its inlet section a removable, rifizid, foraminous,cupshaped basket which supports erem an open-mou h filter bag, and thetransverse downstream end of the filter tank has an outlet opening flowconnected by a conduit section to the inlet of the pump. The pump outletis flow connected by a supply conduit section which extends over the rimof the open top of the cooking post down to its chamber for flowconnection therein of a nozzle assembly. The nozzle assembly is locatedat the end wall of the well opposite that which has the outlet opening,and it includes a pair of lateral nozzles each located at one of themergence shoulder ledges with jet openings thereof directed laterallytoward the opposite outlet opening-equipped end wall for washingparticulate solids off of this shoulder ledge down into the well.Another nozzle of this assembly depends down into the well to direct ajet therefrom along the bulbous bottom section of the latter forsweeping into the outlet opening particulate solids which tend tocollect in this section. A lateral, foraminous, food-supporting rack issupported on the pair of shoulder ledges immediately above the pair oflateral nozzles so that pieces of food thereon will be in the hot fryingzone of the hot oil pooled in the pot chamber. A small aspirating andbleed aperture is provided in this supply conduit section in thevicinity of the intended surface of the pooled hot oil. Burners areprovided externally of thepot chamber on opposite sides of the cold zonedeep well for heating the well walls in their shoulder mergence portionsand therebelow, and the oil pooled thereabove in the fryin'g zone.

10 Claims, 4 Drawing Figures Unitefl States Patent 1 [111 $735,693Pelster et al. May 29, 1973 PATENIE mzslszs SHEET 1 m 3 i r 6* mug I 1"""W" 3 "WW" HOT OIL RECIRCULATING COOKING SYSTEM BACKGROUND AND SUMMARYThe present invention relates to cooking systems for deep fat frying offood, such as chicken parts, that include cooking pots for holdingpooled hot oil in which the food is to be immersed for frying. It isparticularly concerned with such a system which makes provision forrecirculating in the frying cycle the hot oil pooled in the pot chamberfor passage through a filter.

Such a system has been proposed in the Longmire U.S. Pat. No. 3,107,601of Oct. 22, 1963. However, features thereof are undesirable and presentproblems. The oil pooled in the cooking pot chamber is heated byheat-transfer coils immersed in this oil, and while there may be mountedin such a pot chamber a remotelylocated thermostatic element to controlenergization of the immersed heating coils in an attempt to limit themaximum elevation of the temperature of the pooled oil this has provento be inadequate. The temperature of the cooking oil should not exceedabout 425 F. in order to avoid so scorching it as to impart thereto anundesirable flavor to the fried food and which will break it down withlimitation of its useful life. Tests have shown that of the surfaces ofsuch immersed heating coils the temperature of the oil may be raised toa temperature of about 525 F. The filter unit is of complicated andcostly construction and cleaning its interior requires disconnectionthereof from the oil recirculating system and pivoting tilt out of itsupright operative position to allow cleaning access to its interior.This filter also requires the use of an additional heater therein.Thereturned hot oil is spilled into the pot chamber through an inlethole in the top section of the cooking pot sidewall, and no provision ismade for preventing accumulation of crackling and particulate solids inthe bottom of the pot chamber.

The Wagner US. Pat. No. 3,314,416 of Apr. 18, 1967 proposes apressurized cooking pot having a sealing cover, and no hot oil.recirculating system is proposed which could include a filter forcleaning the oil during a cooking cycle. The transversely rectangularcooking pot has a bottom section in which one of a pair of opposedsidewalls is curved inward for convergence thereof to provide arelatively narrow, depending, cold zone deep well. Consequently, a gasburner heat source is located on only one side of this deep well to heatits sidewall on that side and the convergence shoulder thereabove. Suchimbalance of the application of external heat can provide vertical zonesin the pooled oil in which there is appreciable differential in heatdistribution from zone to zone, so that a load of food suspended in abasket which is lowered to the vicinity of the mouth of the cold zonedeep well may be fried to degrees of appreciably different crispness.The food which is supported in the vicinity of the backside of thecooking pot, where heat is not directly applied, may be underdone whilethat located over the position of the gas burner maybecome well fried oroverdone. The narrow closed bottom of the cold zone deep well is flatand horizontal to provide a shelf upon which particulatesolids loosenedfrom the frying food readily can collect. The outlet opening for the potchamber is located in this flat shelf at some undisclosed point alongthe extent thereof and no provision is made for sweeping'such collectedsolids thereinto, for easy removal from the deep well.

These and other problems of the prior art are effectively andefficiently overcome by the present invention.

The present hot oil recirculating cooking system has embodied therein acombination of a chambered cooking pot having sidewalls thereof shapedto define therebetween a relative wide frying zone section andtherebelow a downwardly converging and narrower, depending cold zonedeep well; exterior heating means which applies heat to at least oneside of this deep well, and preferably to both shaped sides thereof, aswell as to at least one overhanging, shoulder ledge-defining portionwhich merges the sidewall of the frying zone section on that side withone of the opposed downwardly converging sidewalls of this deep well;and a discharge nozzle assembly connected to the delivery end ofrecirculating conduit means and located in one side of the bottom of thefrying zone section and the adjacent end of the closed lateral bottomsection of the deep well, so as to wash particulate solids from thisshoulder ledge and to sweep these particulate solids along thelateralwell bottom section into the remote outlet to which the intake of therecirculating conduit means is connected.

Preferred similar shaping of the lower portions of the transverselyspaced and opposed sidewalls of the cooking pot structure definestherebetween the cold zone deep well below the wider frying zone sectionwhich causes the mergences in both sidewalls to define in the vicinityof the bottom of the frying zone section an opposed and laterally spacedpair of such upwardly facing shoulder ledges. Such shaping and mergencesof these opposed sidewalls are similar in an allochiral sense. The coldzone deep well area defined between these opposed sidewalls isclosed'off on opposite ends by preferably flat end walls and at thebottom by an elongated and relatively narrow bottom section which formsan elongated transverse shelf that is generally horizontal fromend-to-end, so that together they define a closed deep well compartment.This deep well compartment is provided with a pot chamber flow outlet inthe vicinity of one of these end walls, and preferably in one of thelatter as a lateral, flow-directing, discharge opening at a point oflowest elevation. In the preferred form the so shaped cold zone deepwell sidewalls are located generally symmetrically with respect to thefrying zone chamber sidewall portions thereabove and between upwardlyextending planes of inner faces of the latter with the well bottomsection arranged substantially intermediate these planes. In thisembodiment the mergence portions of these opposed pot chamber sidewallswhich define the pair of laterally-spaced shoulder ledges and the majorportions of the opposed deep well sidewalls are smoothly convexedinwardly and the well bottom section is smoothly convexed outwardly inbulbous fashion'to discourage collection of particulate solids thereonand to encourage fall thereof into the medial zone of the well bottomsection for general alignment with the lateral, flow-directing,discharge opening.

The exterior heating means which applies heat externally to wallportions of the cooking pot preferably are in the form of a pair of gasburners with each located in one of the side spaces that is bounded bythe inwardlyconvexed portion and the overhanging, shoulderledge-defining portion of the sidewall on that side. Thus each of theseburners transmits heat efficiently by radiation and convection to one ofthe deep well sidewall portions and the overhead shoulder ledgethereabove for effective conductive transfer to the oil in the well andin the superposed frying zone.

The discharge nozzle assembly has a pair of lateral jet directingnozzles with each associated with the transverse end of one of theshoulder ledges which is most remote from the discharge outlet. Eachlateral nozzle preferably is in the form of an elongated, transverselyextending tube closed off at its outer end and mounted immediatelyabove, such as by resting upon, the shoulder ledge with which it isassociated. Each such nozzle tube preferably has a series oflongitudinally spaced apart jet openings in the side thereof which facestoward the other end of the shoulder ledge above which it is mountedeffectively for washing particulate solids off of the latter down intothe well bottom section. These tubular nozzles are oppositely directedfrom common connection to the delivery end of the recirculating conduitmeans with this conduit end preferably being located in the mouth or topof the deep well substantially medially between the pair of shoulderledges. The jets of oil emanating from the pair of lateral nozzles alsoassures an even distribution of heat in the oil pooled in the cookingpot chamber. This nozzle assembly also includes a depending nozzle tubeextending from the conduit delivery end down into the end of the wellbottom section therebelow with its bottom end or tip turned laterallyforward and having at least one jet opening to direct delivery therefromlaterally along the well bottom section toward the remote pot chamberflow outlet opening. Consequently, discharge from this depending nozzletube tip will sweep into this outlet opening particulate solids whichtend to collect in this bottom section.

Means whereby pieces of food may be suspended in the frying zone abovethe lateral nozzles and the jet discharges therefrom may be in the formof a lateral, foraminous rack suitably supported by the cooking potwalls. This rack should have a transverse or peripheral shape generallycomplementary to the transverse sectional shape of the frying zonedefining wider section of the cooking pot for removable nesting in thefrying zone above the lateral oil delivery nozzles, to facilitatecleaning thereof, and with its marginal edges juxtaposed closely to thepot chamber sidewalls in this zone, so as to prevent pieces of foodsupported thereon from falling down therebetween onto the shoulderledges and into the cold zone deep well. Such pieces of food or partsthereof which may otherwise escape into the well bottom section can becaused to travel forward to the discharge outlet or therethrough intothe main valve in the recirculating conduit for checking or blockingflow of oil therethrough. Since in the preferred form of this cookingpot its wider section that circumscribes the frying zone is rectangular,or more specifically square, the periphery of the foodsupporting rackshould also be of such rectilinear shape, with relatively closetolerance existing between its edges and the opposed sidewall innerfaces of the pot chamber thereat. This also avoids the necessity ofbounding such rack by side flanges or upstanding sidewalls. While thefood pieces or chicken parts effectively may be rested directly uponthis lateral rack one may, if he desires, place them in a pan-shapedforaminous basket and immerse the latter to resting support upon thisrack. This rack may be supported in a lateral plane immediately abovethe lateral nozzles by depending legs at its four corners which seatupon the lateral portions of the shoulder ledges.

The discharge section of the recirculating conduit means may be shapedto extend up over the top rim of I the open cooking pot and then down toa cross connector or fitting that may support and flow communicate thetwo lateral nozzles and the depending nozzle to the supply end of thisconduit section. The edge of this food-supporting rack is suitablynotched to permit downward passage of this conduit discharge section orroom for any portion of this cross connector or fitting that may bethere located as may be demanded by the particular design of thearrangement of these parts which locates the lateral nozzle tubesimmediately below this rack. In any event, it is desirable that theselateral tubular nozzles be located below this lateral rack so thatdischarge jets thereof do not impinge directly upon or create vigorouscurrents in the hot oil in which the pieces of food or chicken parts areimmersed, since these can tend to tumble the supported food pieces andseparate therefrom chunks or particulate solids of breading coatingswhich may have been applied thereto.

While it is preferred that the cooking pot be of the open top type itcan be provided with a gasketed lid to convert it to a pressurizedcooking pot, in which case the discharge section of the recirculatingconduit means may pass into the top section through a gasketed hole inone of the walls of this section.

It is a practice to provide on one sidewall inner face a guidance markdictating the elevation of the surface of the oil pooled in the cookingpot chamber, which will assure complete but relatively shallow immersionof the food pieces or chicken parts in the hottest top zone of thefrying oil pool. The discharge or delivery section of the present oilrecirculating conduit system is provided in the vicinity of the commonconnection thereof to the three jet nozzles with a small aspirating andbleed hole at or just above the elevation of this pool surface levelmark. Such small hole will permit aspiration of air under suchconditions as may otherwise tend to siphon back through these nozzlesand the conduit discharge section oil from the pot chamber pool as theoil is being drained from the recirculating system. It will also assurethat when the pooled oil is being drained through the chamber outletopening that which may otherwise be trapped for a time in the supplypassages of the nozzles, and particularly in that of the dependingnozzle which extends down into the deep well bottom section will be morerapidly drained out. Further, this small aspirating and bleed hole willallow drippage therefrom of oil in the elevated loop of the conduitsupply section which extends up over the top of the pot rim and down tothe common connection thereof with the nozzles, at least until the oilpool is sufficiently depleted by drainage through the pot chamber outletopening as to uncover the jet openings in the lateral nozzles.

The recirculating conduit means includes in succession a closed filterunit and a driven pump. While the pump may intervene the cooking potchamber outlet opening and the filter unit it is desirable, in order toavoid fouling the pump with crackling and other particulate solids, suchas breading fines, to interpose the filter unit between the pot chamberoutlet and the pump, so that the latter passes cleaner oil therethrough.This filter unit is in the form of a tank having an inlet end sectionprovided with an inlet opening, preferably in a side of this section,with this inlet opening flow connected to the cooking pot chamber outletthrough a closed, openable, through flow valve. The filter tank inletend section has its end closed by a removable lid which imposes nocontrol upon the connection between the pot chamber outlet and the inletin the filter tank inlet section, and the other end of filter tank isclosed with an outlet opening therein communicated to the pump inlet. Inthe preferred form this filter unit tank is generally cylindrical andcup-shaped with its longitudinal axis extending substantially centrallythrough its end lid, inlet end section and its outlet end section andoriented generally horizontal. If desired, the lid-closed inlet endsection of this filter tank may be slightly lower than the other endsectionso that when the lid is removed complete drainage through theopened end of the inlet end section of the filter tank chamber may beassured. The filter tank chamber has removably nested therein acup-shaped foraminous retainer basket having a generally cylindricalsidewall, a transverse downstream end wall near the tank outlet which iscommunicated to the pump inlet, and an open inlet end located in thevicinity of the tank inlet end section and downstream of the inletopening in the latter, whereby this retainer basket does not interferewith free flow through this filter tank inlet opening. The open inletend of the foraminous retainer basket is gasketed to the wall of filtertank chamber with the sidewall and downstream end wall of this basketspaced inwardly from opposed tank wall portions. A removable open mouthfilter bag is nested in this retainer basket with the open bag mouthremovably anchored to the open inlet end of the basket, the latterserving to hold the bag walls out of contact with the filter tank wallsso as to avoid appreciable blocking of bag perforations by the tankwalls. The filter tank lid has a valved opening therein that isconnectable'to a discharge and suction tube which may have its far enddipped into a storage and supply pan chamber for receiving at will oilfrom the recirculating system without requiring filter tank lid removaland also to allow suction of oil into this system from the storage panchamber with this lid in tankclosing position. I

Other objects of the invention will in part be obvious and will in partappear from reference to'the following detailed description taken inconnection with the'accompanying drawings, wherein like numeralsidentify similar parts throughout, and in which:

FIG. 1 is a side elevational view, with parts broken away and insection, illustrating a preferred embodiment of the hot oilrecirculating cooking system of the present invention;

FIG. 2 is a top plan view, with parts broken away and in section, of theapparatus depicted inFIG. 1;

I FIG. 3 is a front elevational view, with parts broken away and insection, of the apparatus shown in FIGS. 1 and 2; and

FIG. 4 is a perspective view of the filter bag that is embodied in thefilter unit shown in FIGS. 1 to 3 inclusive.

The preferred form of the hot oil recirculating cooking system, which isillustrated in the drawings, includes an open top cooking pot 5preferably housed in a cabinet or casing 6, suitably supported on aplurality of legs 106. As will be best understood from FIG. 2 thetransverse shape of this cooking pot in the upper wider portion thereofis rectangular, preferably square, and defined by a pair of opposed andlaterally spaced sidewalls 7 and 8 and a pair of front and back endwalls 9 and 10. Such walls may be formed from metallic sheet, such asstainless steel.

The opposed sidewalls 7 and 8 are shaped in allochiral fashion to definetherebetween a relatively wide cooking section 11 and a narrower coldzone deep well section 12 with the shaped mergences intervening themproviding lateral, transversely shaped shoulder ledges 13 and 113 (seeFIG. 3). The longitudinally spaced front and back end walls 9 and 10close off these sections to provide a cooking compartment 14 and a coldzone deep well compartment 15 with the latter having opposed sidewalls16 and 17 and closed off by a longitudinally extending bottom section18. The chamber of this cooking pot 5, including its cooking compartment14 and cold zone deep well compartment 15, has an outlet opening in thecold zone deep well bottom section 18 at a point of lowest elevation,such as at 19, which is suitably flow connected by pipe fittings 20 tothe inlet end of a main through flow manual valve 21 which has a manualmanipulative handle 22 shown in the valve-closing position in thedrawings.

As is conventional, the back end wall 10 may be provided with an oilpool surface level mark, such as at 23 in FIG. 1, to guide the depth ofthe pool of oil in the cooking pot chamber which is supplied thereto bythe operator, so as to limit the pool surface, indicated in broken linesat 24, to that which is sufficient to define a frying zone 25 in whichthe pieces of food or chicken parts are to be completely immersed forthe frying operation.

Suitable means for supporting the pieces of food or chicken parts withinthe frying zone 25 may be in the form of a stainless steel, foraminousrack or screen 26 which is, as best seen in FIG. 2, complementary inshape to the transverse shape of the cooking compartment l4 and boundedby a rectangular frame 27. This food-supporting rack 26 may be suitablysupported in the frying zone 25 in any desired manner, but, since itmust be removable for easy cleaning it is provided at its four cornerswith depending short legs 28 which seat or rest upon the lateralshoulder ledges 13 and 113. The rack 26 is positioned relative to theoil pool surface 24 so that the food pieces, diagrammatically indicatedin broken lines in FIGS. 1 and 3, will be completely immersed in the oilin this frying zone, preferably at shallow depth.

The cooking pot chamber has its outlet opening 19 communicated bysuitable conduit means which includes the main valve 21, a filter unit29, a pump 30, and oil discharge or delivery structure in the form of anozzle assembly 31. As will be seen from FIGS. 1 and 2 the filter unit29 is in the form of a cylindrical tank 32 having an inlet section 33provided with an open end and with its other downstream end 341 closedby a transverse end wall. The inlet end section 3 3 is closed by aremovable cap 35 which is suitably gasketed to the open end of thefilter tank. This inlet section preferably has pivotally mounted theretoa yoke 36 which carries a pressure applying manual screw 37 with itsinner end adapted to engage the central portion of the lid 35, wherebythis lid may be snugly clamped to the open end of the filter tank 32 toclose the latter. The inlet end section 33 is provided on the sidethereof with a fixed coupling 38 which is flow connected by a nipple 38ato the outlet opening of the main valve 21 (FIGS. 2 and 3) having itsbore communicated by an inlet opening 39 which leads to the interior ofthis inlet end section. Flow through the inlet opening 39 thus is notaffected by the mount or removal of the end lid 35.

The main cup-shaped chamber 40 (FIG. 1) of the filter tank 32 has nestedtherein a cup-shaped, foraminous retainer basket 41 which is preferablyformed of expanded metal and provided with an upstream open mouth,suitably spaced annularly inward at 42 with respect to the chamber wall.This retainer basket has its sidewall and downstream transverse end wallsuitably spaced from the inner surfaces of the main chamber 40 of thefilter tank 32 in order to avoid interference with free flow of oiltherethrough to an outlet coupling 43 fixed to the transvese end wall34. As is illustrated in FIG. 1 the retainer basket 41 has insertedtherein a cup-shaped filter bag 44 with its open mouth 45 circumscribedby a hem 46 into which is threaded a C- shaped loop 47 of a manipulativehandle 48, so that the latter will facilitate removal of the filter bagfrom the retainer basket. It will be understood from FIG. 1 that thehandle loop 47 is of such dimensions relative to the circumference ofthe inner wall of the filter tank chamber 40 and an annular spacing ringat 42 of the retainer basket as to jam securely against this inner walland this ring in a substantially leak-proof manner when the filter bag44 is inserted in this basket and both are mounted within the filtertank chamber. The perforations of the fabric of the filter bag 44 thusare prevented from being blocked by contact with the filter tank chamberwall.

The filter tank closing lid 35 is equipped with an outlet opening at alow point into which a nipple 49 is threaded for threadably connectingthereto a through flow valve 50 having a manual manipulating handle 51with its outlet end connected by a threaded nipple 52 to a discharge andsuction hose 53 with its open end 54 dipped into an oil supply andstorage tank or pan 55. For convenience of transport the oil supply andstorage tank 55 may be supported on suitable rollers or casters (notshown).

The outlet coupling 43 which is mounted on the otherwise closedtransverse end wall 34 of the filter tank 32 is suitably connected by apipe or tube 56 to intake 57 of the pump 30. The pump 30 is driven by anelectric motor 58 which is suitably supported by a bracket 59 mounted inany suitable manner to the casing or cabinet structure 6. The pumpdriving motor 58 has its power supply circuitry provided with a suitablemanual switch and a thermostat switch (not shown), with this thermostatswitch provided with a suitable temperature sensing bulb (not shown)which may be connected through a wall of the cooking pot chamber in thehot frying zone thereof, in conventional manner.

The outlet 60 of the pump 30 is connected by a supply or discharge pipeor tube 61 which, for convenience, may extend over the rim of the opentop of the cooking pot and then down to communicative connection withthe discharge nozzle assembly 31. This nozzle discharge assembly 31includes nozzle means to direct discharge jets laterally along themergence shoulder ledges l3 and 113 for washing particulate solids offof the latter down into the bottom section 18 of the cold zone deep well10. For this purpose, the nozzle assembly may include a cross fitting 62into oppositely directed, lateral outlets of which are mounted suitablefittings for supporting in flow communicating manner tubular lateralnozzles 63 which have their outer ends suitably closed off. Theselateral nozzles 63 are conveniently supported by seating directly uponthe shoulder ledges 13 and 113. Each of the lateral jet directingnozzles 63 is conveniently provided with a series of longitudinallyspaced-apart jet openings 64 in the side thereof which faces toward theother end of the shoulder ledge upon which it is seated. These lateraljet directing nozzles 63 are located in the vicinity of the transverseends of the shoulder ledges which are farthest away from the pot chamberflow outlet 19, so that the jets emanating from the jet openings 64 willdirect flow along the shoulder ledges for wash thereof while developingcurrents in the oil pool in the general direction of the location ofsuch outlet, for facilitating the recirculation of the hot oil, duringthe frying operation, through the frying zone toward the pot chamberoutlet for return flow therefrom through the filter unit 29 and theimpelling pump 30.

The downwardly directed opening of the cross fitting 62 supports and isflow connected to an additional nozzle in the form ofa depending tube 65which is medially located between the opposed sidewalls 16 and 17 of thecold zone deep well 10 and into the bottom section 18 of the latter. Thetip end 66 of this nozzle tube 65 is turned forward so that a dischargejet opening in the latter is directed laterally along this bottomsection toward the pot chamber flow outlet for sweeping into this outletparticulate solids which tend to collect in this section. The back sideof the depending nozzle tube 65 is provided, preferably just above theforward bend that defines its tip end nozzle 66, with a jet opening at66a so as to assure cleaning out the area therebehind.

It will be seen from FIG. 2 that the circumscribing frame 27 of thefood-supporting rack 26 is suitably provided with a notch 67 which, whenthis rack is supported upon the shoulder ledges l3 and 113 by its legs28, will accommodate such portions of the cross fitting 62 as arelocated in the same transverse or lateral plane. This will avoidinterference by the supply or discharge conduit and nozzle structurewith ready removal of this rack to allow cleaning thereof outside of thecooking pot. For clarity of illustration in FIG. 3 an appreciable spacehas been indicated as intervening the lateral nozzles 63 and the foodsupporting rack 26. However, it is to be understood that it is preferredto locate this rack down as close as possible to such lateral nozzlestructure and the lateral portions of the cross fitting 62 with the racksupporting legs 28 being of such short lengths as will permit this closelocation.

As will be best seen from FIG. 3 the cold zone deep well sidewalls l6and 17 are located generally symmetrically with respect to the fryingzone chamber sidewalls 7 and 8 and between upwardly extending planes ofinner faces of the latter with the well bottom section 18 arrangedsubstantially intermediate these planes. The depending nozzle 65preferably is centered relative thereto for efficient cleaning of thecold zone bottom section 18 in order to assure that all of thecracklings and other particulate solids, such as flour fines, will bewashed therefrom into and through the cooking pot discharge outletopening 19, since otherwise they may tend to accumulate on the side mostwidely spaced from the jet flow emanating from the nozzle tip 66 as tocause flow clogging ahead of and at the mouth of the discharge outlet19.

It will further be noted from FIG. 3 that the mergence portions of theopposed sidewalls of the cooking pot structure with the opposedsidewalls 16 and 17 of the cold zone deep well, which define theintervening shoulder ledges 13 and 113, are smoothly convexed inwardlyfor encouraging smooth flow therealong and down into the bottom section18 of this well. This bottom section of the deep well is also smoothlyconvexed outwardly in bulbous fashion for similarly encouraging smoothflow toward the longitudinal center of the latter for facilitatingcollection of particulate solids therealong in substantial alignmentbetween the depending nozzle tip 66 and the cooking pot discharge outlet19.

Such symmetrical shaping of the opposed sidewalls of the cooking potstructure define exterior thereof a pair of outer side spaces 68 and 168with each being bounded by the inwardly convexed portion and theoverhanging, shoulder ledge-defining portion of the sidewall on thatside. Within each of the exterior spaces 68 and 168 is located one of apair of gas burners 69 (FIG. 3) which will transmit heat efficiently byradiation and convection to the deep well sidewall portion and theoverhead shoulder ledge thereof on that side for effective conductivetransfer to the oil in the deep well and in the superposed frying zone.As has been previously indicated these gas burners are suitablyassociated with gas supply equipment through which How of burner gas iscontrolled by the temperature control equipment which includes athermostat bulb that is associated with the oil pooled in the fryingzone.

In connection with FIG. 1 it has been previously indicated that theinner face of the cooking pot end wall preferably has its inner faceprovided with an oil surface level mark 23. At the level of this markthe oil discharge or supply equipment leading to the nozzle assembly 31is provided with a small aspirating and bleed hole 79 at or slightlybelow the level of the pool surface 24 as dictated by the level mark 23.The relative dimension of this aspirating and bleed hole may be bestunderstood if, by way of example, it is about 3/32nds of an inch indiameter in the event that the supply pipe or tube has a passage that isabout k inch in diameter. Such small aspirating and bleed opening willpermit aspiration of air under such conditions as may otherwise tend tosiphon back through the delivery nozzles 63 and 65 and the conduitdischarge section 61 oil from the pot chamber pool as the oil is beingdrained from the recirculating system out through the opened filter tank29. It will also assure that when the pooled oil is being drainedthrough the pot chamber outlet opening 19 that which may otherwise betrapped for a time in the supply passages of the nozzles, andparticularly in that of the depending nozzle 65, will be more rapidlydrained out. Further, this small aspirating and bleed hole will allowdrippage therefrom of oil in the elevated loop of the conduit supplysection, which includes the conduit section 61 that extends up over thetop of the pot rim and down to the cross fitting of the nozzle assembly31, at least until the oil pool is sufficiently depleted by drainagethrough the pot chamber outlet opening as to uncover the jet openings 64in the lateral nozzles 63.

In use and operation of the hot oil recirculating cooking system of thepresent invention let it be assumed that with the main control valve 21closed sufficient oil is supplied in any suitable manner to the cookingpot chamber as to fill up the cold zone deep well compartmerit 15 andthe frying compartment 14 to the level 24 as dictated by the mark 23.The temperature of the pooled oil may be brought up to a predeterminedtemperature of about 350 F. by manual and/or automatic control of theburners 69. During this heating the pump 30 will be operated torecirculate the oil from the cooking pot discharge outlet 19 through theassembled and closed filter unit 29, the pump 30 and the discharge orsupply assembly 31 for even distribution of heat. After a predeterminedperiod of such recirculation of the oil, which for certain service maybe about 10 minutes, with the recirculating oil pooled in the cookingpot chamber at about 350 F., the suitably coated or breaded food piecesor chicken parts will be dropped into the frying zone 25 down upon thesupport rack 26. For this service a frying time of about l3 minutes mayhave been selected after which the food pieces or chicken parts will belifted from immersion in the frying zone section 25 of the pooled andrecirculating oil, and allowed to drain. The recirculating of the oilwill be continued thereafter for a period, which may be about 10minutes. This cycle of continuous circulation of the hot oil before,during, and after the frying will then be repeated throughout a daysproduction. After the last such cycle of operation when the apparatus isto be shut down for the night the pump will be stopped and the maindrain valve 21 manually closed. The oil supply and storage tank or pan55 should then be moved to beneath the lid-closed end of the inletsection 33 of the filter tank 32 and the discharge end 54 of hose 53.The lid drain valve 50 is then opened to drain the oil from the filterunit 29. After this drainage has stopped the lid 35 will be loosened bybacking off the tightening screw 37, so as to crack the lid seal withoutcompletely freeing the lid, thereby insuring complete drainage. The lidclamping screw is then completely loosened and the yoke 36 is swung upto free the lid so that the inlet end section of the filter tank 32 isopened for permitting drainage of oil therefrom into the supply anddrainage tank or pan, so that substantially all of the oil will fiowfreely from the filter tank chamber by virtue of the fact that the openend of the filter tank is slightly lower than the closed discharge end34 thereof. The retainer basket 41 and the filter bag 44 housed thereinwill then be removed and the oil will be drained from the cooking potchamber through the discharge outlet 19 upon opening of the main drainvalve 21. Then the interior of the open filter tank 32 and the cookingpot chamber will be thoroughly cleaned, oil washed and wiped down. 7

If it is desired to store the filtered oil in the cooking pot chamberovernight, after the filter bag 445 has been cleaned and replaced in theretainer basket 41 these may be replaced in the filter tank chamber 40,and the lid 35 replaced. With the main valve 21 reclosed .and the lidvalve 50 open the suction hose 53 will have its end 54 dipped into thesupply tank or pan chamber 55 and the pump 30 may be restarted to pumpthe oil back into the cooking pot chamber to pool the surface 24 of theoil therein at the level of the mark 23 for overnight storage. With themain valve 21 still closed, the lid of the filter tank may be removedand the retainer basket and filter bag removed to leave the filter tankchamber open overnight, for assembly the next morning of the parts ofthe filter unit before beginning the first cycle of operation the nextday.

It will be understood that variations of conditioning for overnightidleness of the apparatus may be prac- .ticed with ease, such as byomitting the insertion into the filter tank of the cleaned filter bagand the retainer basket for repumping the oil back into the cooking potchamber for overnight storage. Also, for drainage of the filter tankchamber and the cooking pot chamber, instead of removing the lid 35thereof the lid valve 50 may be opened for effecting such drainagethrough the hose 53 into the discharge and supply tank or pan 55, andthen the filter tank lid may be removed so that the filter tank may beleft open overnight.

When overnight storage of oil in the deep well compartment 1S and fryingzone section 25 of the pot compartment 14 is practiced, reconditioningthe apparatus the next morning for the first frying operation requiresreplacement of the retainer basket 41 with a clean filter bag 44 nestedtherein and reclosure of the filter tank 32 by its lid 35 with the lidvalve 50 closed. The main valve 21 will be opened and the burners 69will be fired to apply heat to the oil stored in the frying zone anddeep well compartments 25 and 15. When the temperature of the pooled oilin the frying zone compartment is raised to 350 F. the oil in the deepwell compartment 15 is stirred with a long handled spoon, the main drainvalve 21 is opened, and the recirculating pump 30 is started to run forthe pre-frying period before the food pieces or chicken parts aredropped upon the support rack 26 to immersion in the hot oil in thefrying zone 25.

It will be understood that by recirculating the heated oil through theexternal conduit system, the frying zone 25 of the cooking potcompartment 14 and the deep well compartment 15 assures even heatdistribution throughout the oil in the cooking pot chamber which assuresuniform color of cooked food pieces or chicken parts. This even heatdistribution permits maintenance of the predetermined maximumtemperature of the oil pooled in the cooking pot chamber withintolerance limits which prevents overheating to a degree that can scorchthe oil to impart an undesirable flavor to the fired food. Theconstruction of the various parts permits ready nesting assembly ofthose which are not mechanically connected together for facilitatingremoval for easy cleaning. Also, by repeated filtering of the oil duringand between successive cycles of frying it is maintained in asufficiently clean condition as to permit storage thereof overnight inthe cooking pot chamber for immediate use the next morning to begin thesuccessive cooking operations.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above construction withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having described our invention, what we claim as new and desire tosecure by Letters Patent is the novel subjects matter defined in thefollowing claims.

1. A hot oil recirculating cooking system for deep fat frying food, suchas chicken parts, including a cooking pot that has a chamber in whichsuch food is to be fried by immersion in a pool of the hot oil during acooking cycle, said pot chamber having a flow outlet in the bottom areathereof and an inlet in the top area thereof,

conduit means providing a through flow path between said pot chamberoutlet and inlet including a pump and an openable closed filter tankhaving a chamber containing removable filtering means, characterized bythe combination of 1. means defining in the bottom area of said potchamber a depending cold zone deep well having transversely spaced andopposed sidewalls merged with more widely spaced pot chamber sidewallsthereabove with the latter defining therebetween the frying zone abovethe well cold zone, the mergence providing at least one upwardly facingshoulder ledge in the vicinity of the bottom of the frying zone, saidcold zone well having an elongated and relatively narrow, well-closingbottom section which extends laterally between and in the directiongenerally parallel to the surfaces of its transversely spaced sidewallswith the pot chamber flow outlet located in the vicinity of one closedend of said well bottom section;

2. heating means exterior of said pot to apply heat externally of saidpot chamber to at least one of said well sidewalls and to said mergenceof this sidewall with the frying zone sidewall thereabove in thevicinity of its shoulder ledge; and

3. a discharge nozzle assembly flow connected to said conduit means andlocated in the pot chamber frying zone and the cold zone well, thisassembly including nozzle means to direct discharge jets laterally alongsaid mergence shoulder ledge for washing particulate solids off of thelatter down into the bottom section of said well, and additional nozzlemeans depending down into said well bottom section to the vicinity ofthe other closed end of the latter to direct at least one discharge jetlaterally along said bottom section toward the pot chamber flow outletfor sweeping into this outlet particulate solids which tend to collectin this section.

2. The cooking system as defined in claim 1 characterized by said coldzone well sidewalls being located generally symmetrically with respectto said frying zone chamber sidewalls and between upwardly extendingplanes of inner faces of the latter sidewalls with the well bottomsection arranged substantially intermediate these planes, a pair ofsimilar upwardly facing and transversely spaced mergence shoulder ledgesbeing provided thereby, and a pair of said heating means being providedwith each arranged relative to one of said mergence shoulder ledges andthe well sidewall which is associated therewith with the well bottomsection being arranged between said pair of heating means, said nozzleassembly having a pair of said lateral jet directing nozzle means witheach associated with one of said mergence shoulder ledges for suchwashing thereof.

3. The cooking system as defined in claim 2 characterized by theprovision of a lateral food-supporting, foraminous rack which is ofperipheral shape substantially complementary to the transverse sectionalshape of the frying zone, and removably nested in this frying zone abovesaid pair of lateral jet directing nozzle means.

4. The cooking system as defined in claim 3 characterized by said pairof lateral jet directing nozzles being in the form of a pair ofoppositely directed and trans versely extending tubes closed off attheir outer ends and respectively mounted immediately above said merl3gence shoulder ledges in the vicinity of the transverse ends thereofwhich are located farthest away from the pot chamber flow outlet andimmediately above these shoulder ledges for wash thereof, each of saidnozzle tubes having a series of longitudinally spaced-apart jet openingsin the side thereof which faces toward the other end of the shoulderledge above which it is mounted.

5. The cooking system as defined in claim 4 characterized by a pluralityof support members depending from said rack and resting upon saidmergence shoulder ledges to support said rack in said frying zone in alateral plane immediately above said pair of lateral jet directingnozzle means.

6. The cooking system as defined in claim 3 characterized by saidconduit means having a discharge section leading down through saidfrying zone to said discharge nozzle assembly which is equipped with asmall aspirating and bleed hole in a side thereof that is located in thevicinity of a predetermined level of the surface of the intended hot oilpool in the cooking chamber frying zone in which said food-supportingrack and its food load will be immersed.

7. The cooking system as defined in claim 2 characterized by theprovision of said pot chamber flow outlet being a lateral flow-directingopening located in the end of said well bottom section at a point oflowest elevation toward which said depending nozzle means directs jetdischarge. I

8. The cooking system as defined in claim 1 characterized by saidconduit means having an intake section connected to said pot chamberoutlet and extending from the latter to an inlet opening in an inlet endsection of said filter tank and equipped with a normally closed,openable, through flow valve; said tank having its inlet end sectionclosed by a removable lid with its other downstream end section beingclosed and equipped with an outlet communicated to the inlet of saidpump by another section of said conduit means.

9. The cooking system as defined in claim 8 characterized by said filtertank being in the form of a generally cylindrical, cup-shaped tankhaving its longitudinal axis extending substantially centrally throughits lid, inlet end section and its outlet end section and orientedgenerally horizontal, said tank chamber having removably nested thereina cup-shaped foraminous retainer basket having a generally cylindricalsidewall, a transverse downstream end wall and an open inlet end locatedin the vicinity of said tank inlet section downstream of the inletopening in the latter and gasketed to the wall of said tank chamber withits sidewall and downstream end wall spaced inwardly from opposed tankwall portions, and a removable open mouth filter bag nested in saidretainer basket with its open mouth removably anchored to the open inletend of said retainer basket.

10. The cooking system as defined in claim 9 characterized by saidfilter tank lid having a valved opening therein connectable to adischarge and suction tube.

1. A hot oil recirculating cooking system for deep fat frying food, such as chicken parts, including a cooking pot that has a chamber in which such food is to be fried by immersion in a pool of the hot oil during a cooking cycle, said pot chamber having a flow outlet in the bottom area thereof and an inlet in the top area thereof, conduit means providing a through flow path between said pot chamber outlet and inlet including a pump and an openable closed filter tank having a chamber containing removable filtering means, characterized by the combination of
 1. means defining in the bottom area of said pot chamber a depending cold zone deep well having transversely spaced and opposed sidewalls merged with more widely spaced pot chamber sidewalls thereabove with the latter defining therebetween the frying zone above the well cold zone, the mergence providing at least one upwardly facing shoulder ledge in the vicinity of the bottom of the frying zone, said cold zone well having an elongated and relatively narrow, well-closing bottom section which extends laterally between and in the direction generally parallel to the surfaces of its transversely spaced sidewalls with the pot chamber flow outlet located in the vicinity of one closeD end of said well bottom section;
 2. heating means exterior of said pot to apply heat externally of said pot chamber to at least one of said well sidewalls and to said mergence of this sidewall with the frying zone sidewall thereabove in the vicinity of its shoulder ledge; and
 3. a discharge nozzle assembly flow connected to said conduit means and located in the pot chamber frying zone and the cold zone well, this assembly including nozzle means to direct discharge jets laterally along said mergence shoulder ledge for washing particulate solids off of the latter down into the bottom section of said well, and additional nozzle means depending down into said well bottom section to the vicinity of the other closed end of the latter to direct at least one discharge jet laterally along said bottom section toward the pot chamber flow outlet for sweeping into this outlet particulate solids which tend to collect in this section.
 2. heating means exterior of said pot to apply heat externally of said pot chamber to at least one of said well sidewalls and to said mergence of this sidewall with the frying zone sidewall thereabove in the vicinity of its shoulder ledge; and
 2. The cooking system as defined in claim 1 characterized by said cold zone well sidewalls being located generally symmetrically with respect to said frying zone chamber sidewalls and between upwardly extending planes of inner faces of the latter sidewalls with the well bottom section arranged substantially intermediate these planes, a pair of similar upwardly facing and transversely spaced mergence shoulder ledges being provided thereby, and a pair of said heating means being provided with each arranged relative to one of said mergence shoulder ledges and the well sidewall which is associated therewith with the well bottom section being arranged between said pair of heating means, said nozzle assembly having a pair of said lateral jet directing nozzle means with each associated with one of said mergence shoulder ledges for such washing thereof.
 3. The cooking system as defined in claim 2 characterized by the provision of a lateral food-supporting, foraminous rack which is of peripheral shape substantially complementary to the transverse sectional shape of the frying zone, and removably nested in this frying zone above said pair of lateral jet directing nozzle means.
 3. a discharge nozzle assembly flow connected to said conduit means and located in the pot chamber frying zone and the cold zone well, this assembly including nozzle means to direct discharge jets laterally along said mergence shoulder ledge for washing particulate solids off of the latter down into the bottom section of said well, and additional nozzle means depending down into said well bottom section to the vicinity of the other closed end of the latter to direct at least one discharge jet laterally along said bottom section toward the pot chamber flow outlet for sweeping into this outlet particulate solids which tend to collect in this section.
 4. The cooking system as defined in claim 3 characterized by said pair of lateral jet directing nozzles being in the form of a pair of oppositely directed and transversely extending tubes closed off at their outer ends and respectively mounted immediately above said mergence shoulder ledges in the vicinity of the transverse ends thereof which are located farthest away from the pot chamber flow outlet and immediately above these shoulder ledges for wash thereof, each of said nozzle tubes having a series of longitudinally spaced-apart jet openings in the side thereof which faces toward the other end of the shoulder ledge above which it is mounted.
 5. The cooking system as defined in claim 4 characterized by a plurality of support members depending from said rack and resting upon said mergence shoulder ledges to support said rack in said frying zone in a lateral plane immediately above said pair of lateral jet directing nozzle means.
 6. The cooking system as defined in claim 3 characterized by said conduit means having a discharge section leading down through said frying zone to said discharge nozzle assembly which is equipped with a small aspirating and bleed hole in a side thereof that is located in the vicinity of a predetermined level of the surface of the intended hot oil pool in the cooking chamber frying zone in which said food-supporting rack and its food load will be immersed.
 7. The cooking system as defined in claim 2 characterized by the provision of said pot chamber flow outlet being a lateral flow-directing opening located in the end of said well bottom section at a point of lowest elevation toward which said depending nozzle means directs jet discharge.
 8. The cooking system as defined in claim 1 characterized by said conduit means having an intake section connected to said pot chamber outlet and extending from the latter to an inlet openinG in an inlet end section of said filter tank and equipped with a normally closed, openable, through flow valve; said tank having its inlet end section closed by a removable lid with its other downstream end section being closed and equipped with an outlet communicated to the inlet of said pump by another section of said conduit means.
 9. The cooking system as defined in claim 8 characterized by said filter tank being in the form of a generally cylindrical, cup-shaped tank having its longitudinal axis extending substantially centrally through its lid, inlet end section and its outlet end section and oriented generally horizontal, said tank chamber having removably nested therein a cup-shaped foraminous retainer basket having a generally cylindrical sidewall, a transverse downstream end wall and an open inlet end located in the vicinity of said tank inlet section downstream of the inlet opening in the latter and gasketed to the wall of said tank chamber with its sidewall and downstream end wall spaced inwardly from opposed tank wall portions, and a removable open mouth filter bag nested in said retainer basket with its open mouth removably anchored to the open inlet end of said retainer basket.
 10. The cooking system as defined in claim 9 characterized by said filter tank lid having a valved opening therein connectable to a discharge and suction tube. 